Asynchronous JavaScript and XML (Ajax) is a web page development technology for creating interactive web page applications. For a conventional web page, if a portion of the web page content has been updated, a user can see the updated content only after the entire web page is refreshed. With an Ajax web page however, a user can obtain the updated portion of the content without refreshing the entire web page. From the perspective of a network device, this avoids repeatedly transmitting unaltered information and thus saves network bandwidth and reduces server workload. From a user's perspective, waiting times during web page browsing can be effectively reduced, thus improving user experience.
A search engine is a system that can collect, organize and process Internet information with the capability of providing search services to users. Currently, the search engine has become one of the indispensible auxiliary tools of Internet surfing experience for users. A web crawler, being an important component of the search engine, can automatically retrieve web page content and provide real-time, updated data to the search engine. Though conventional web pages can be supported, existing web crawlers fail to effectively retrieve contents that are generated dynamically by Ajax on Ajax web pages. As a result, dynamic contents on Ajax web pages cannot be collected by the search engine, leading to a failure of the search engine to provide a complete content search service to the user.